Geology topics

David J. Lang

Publications and source records attributed to David J. Lang.

4 recordsLinked to original sources

USGS1982

Water quality of the three major tributaries to the Chesapeake Bay, the Susquehanna, Potomac, and James Rivers, January 1979 - April 1981

Water-quality constituent loads at the Fall Line stations of the Susquehanna, Potomac, and James Rivers, the three major tributaries to the Chesapeake Bay, can be estimated with reasonable accuracy by regression techniques, especially for wet periods of 1 year or more. Net transport of all nutrient species and most other constituents, especially those found in greatest concentrations associated with suspended material, is dominated by a few spring and storm-related high-flow events. Atrazine and 2,4-D are the two herbicides most consistently detected at the Fall Line of the Susquehanna and Potomac Rivers. Concentrations of total residual chlorine and low-molecular-weight, halogenated hydrocarbons at selected sites in estuaries to the upper Bay are generally at or below detection limits. When compared to the two other major tributaries, the James River has the lowest discharge-weighted-sulfate concentrations, presumably because of the lack of coal mining activity in this basin. This river also has lower total nitrogen concentrations. Ammonia concentrations and loads are decreasing at all three Fall Line stations, as is orthophosphate in the Susquehanna and Potomac Rivers. Slight increases in total nitrogen and nitrite plus nitrate concentrations in the Susquehanna River from 1969 to 1980 may warrant continued monitoring. Analyses of data for this report confirm the previous suggestion that when water discharge of the Susquehanna River at Conowingo, Maryland, is below about 400,000 cubic feet per second, sediment, with sorbed nutrients and other constituents, is deposited behind the three hydroelectric dams on this river between Harrisburg, Pennsylvania, and its mouth. Discharges above 400,000 cubic feet per second resuspend these sediments and transport constituent loads to the Bay well in excess of loads transported by the Susquehanna River at Harrisburg. In addition to precipitation quantity and intensity, antecedent conditions and season of the year play a major role in the transport of sediments and their associated chemical constituents at all three stations.

James River, Potomac River, Susquehanna River↗

USGS1980

Aquifer recharge from the 1969 and 1978 floods in the Mojave River basin, California

The Mojave River basin, a high desert area in southwestern San Bernardino County, Calif., received 2.3 times the normal annual precipitation during the 1969 and 1978 water years. Precipitation in the mountainous upper part of the watershed is the primary source of flow in the Mojave River. Total precipitation at Lake Arrowhead, representative of the mountainous area, was 98 inches in the 1969 water year and 93 inches in the 1978 water year. Of these totals, 94 inches in 1969 and 88 inches in 1978 fell during the rainy season, December through April. The resulting flood period in 1969 produced an instantaneous peak discharge of 18,000 cubic feet per second at Afton, about 100 miles downstream from Lake Arrowhead. This discharge had an approximate flood-recurrence interval of 30 years. An instantaneous peak of 24,800 cubic feet per second was measured during the 1978 floods at Deep Creek. This discharge had an approximate flood-recurrence interval of 20 years. A comparison of the hydrologic data for the 1969 and 1978 flood periods indicates that although more precipitation occurred in 1969, more recharge occurred in 1978. The factors that caused the greater recharge were: (1) The more evenly distributed precipitation from December 1977 to April 1978, allowing for more uniform surface-water runoff in the Mojave River; (2) the dams constructed in the upper basin after 1969, which regulated floodflow peaks and allowed more water to stay in the basin; and (3) the lower water level in the aquifer in 1978, which made more space available to store the recharge water. Total recharge resulting from the floods is estimated to have been 245,000 acre-feet in the 1969 water year and 282,000 acre-feet in 1978. At present (1979) costs of water from Silverwood Lake, the 1969 recharge would be worth about $4.6 million and the 1978 recharge about $5.2 million. If the water were derived from the turnout of the California Aqueduct, the undelivered costs would be about $4.9 million for 1969 and $5.6 million for 1978.

California↗

USGS1980

Water-quality monitoring of three major tributaries to the Chesapeake Bay: Interim data report

The U.S. Geological Survey is monitoring the water quality of three major tributaries to Chesapeake Bay at their fall lines to obtain estimates of constituent inputs potentially available to the bay. The monitoring sites are: Susquehanna River at Conowingo, Md.; Potomac River at Washington, D.C.; and James River at Cartersville, Va. Water-quality data collected from October 1978 to April 1980 are presented in tables. Concentrations of major ions, nutrient and carbon species, metals, pesticides, suspended sediment, and other selected constituents are presented for a range of flows. The mean, standard deviation, minimum, maximum, and median values for each constituent were determined by standard methods and are presented for each sampling station. Bivariate linear regressions were run for all constituents versus streamf low, specific conductance, and suspended sediment. Those relationships exhibiting coefficients of determination (R ) greater than 0.50 are tabulated.

James River, Potomac River, Susquehanna River↗

USGS1979

Water-resources data, 1970-75, for Perris Valley and vicinity, Riverside County, California

In 1969 the U.S. Geological Survey began in Perris Valley, Calif., to determine changes in the hydrologic regime as a rural area becomes urbanized. The investigations spanned several years when precipitation was below normal in most of southern California. Surface-water records were collected for a 6-year period at 21 sites, and continuous precipitation records were obtained at four sites. Ground-water levels were tabulated from historical data at selected wells for 1941, 1968, and 1970. Water quality was monitored at several wells in the valley, and sediment data were collected at three surface-water gages. There was little increase in urbanization during the investigation.

California↗